Mounting adapter



FIG. 1 is a perspective view of a mounting adapter, showing my new design;

FIG. 2 is a side view thereof, the side opposite that shown in FIG. 2 being the mirror image thereof;

FIG. 3 is an end view thereof from the right of FIG. 2; and,

FIG. 4 is an end view thereof from the left of FIG. 2. 

The ornamental design for a mounting adapter, as shown and described. 